Thermal management system

ABSTRACT

A system for managing thermal transfer in at least one of an aircraft or a gas turbine engine includes a first engine system utilizing an oil for heat transfer. The oil of the first system has a temperature limit of at least about 500° F. The system additionally includes a fuel system having a deoxygenation unit for deoxygenating fuel in the fuel system, as well as a fuel-oil heat exchanger located downstream of the deoxygenation unit. The fuel-oil heat exchanger is in thermal communication with the oil in the first engine system and the fuel in the fuel system for transferring heat from the oil in the first engine system to the fuel in the fuel system.

PRIORITY INFORMATION

The present application claims priority to, and is a continuation of,U.S. patent application Ser. No. 15/041,224 titled “Thermal ManagementSystem” filed on Feb. 11, 2016, which in turn claims priority to, and isa continuation of, U.S. patent application Ser. No. 14/962,313 titled“Thermal Management System” filed on Dec. 8, 2015, each of theseapplications are incorporated by reference herein.

FIELD OF THE INVENTION

The present subject matter relates generally to a thermal managementsystem for at least one of an aircraft and a gas turbine engine.

BACKGROUND OF THE INVENTION

A gas turbine engine generally includes a fan and a core arranged inflow communication with one another. The core of the gas turbine enginegenerally includes, in serial flow order, a compressor section, acombustion section, a turbine section, and an exhaust section. Inoperation, at least a portion of air over the fan is provided to aninlet of the core. Such portion of the air is progressively compressedby the compressor section until it reaches the combustion section. Fuelis mixed with the compressed air and burned within the combustionsection to provide combustion gases. The combustion gases are routedfrom the combustion section through the turbine section to drive one ormore turbines within the turbine section. The one or more turbineswithin the turbine section maybe coupled to one or more compressors ofthe compressor section via respective shaft(s). The combustion gases arethen routed through the exhaust section, e.g., to atmosphere.

The gas turbine engines accordingly include a variety of rotatingcomponents, which may experience hot operating conditions—the hotoperating conditions potentially limiting engine component life. Moderngas turbine engines employ sophisticated thermal management systems tocool these rotating components. Unfortunately, the commonly used thermalheat sinks may not provide a desired amount of heat removal.

At the same time, it desirable to heat fuel delivered to the combustionsection of the gas turbine engine to increase an engine efficiency. Fueltemperature, however, may be limited by the formation of insolubleproducts referred to as “coke”. Coke may form when hydrocarbon fuelcontaining oxygen is heated beyond a certain temperature (e.g. above250° F. or 121° C.). Coke deposits may potentially limit fuel systemcomponent life.

Accordingly, a gas turbine engine capable of efficiently removing heatfrom various rotating components of the gas turbine engine whileadditionally heating fuel to be delivered to the combustion section ofthe gas turbine engine would be useful. More particularly, a gas turbineengine capable of efficiently removing heat from various rotatingcomponents of the gas turbine engine while additionally heating fuel tobe delivered to the combustion section without forming Coke within suchfuel would be especially beneficial.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In one exemplary embodiment of the present disclosure, a system formanaging thermal transfer in at least one of an aircraft or a gasturbine engine is provided. The system includes a first engine systemutilizing an oil for heat transfer, the oil having a temperature limitof at least about 500 degrees Fahrenheit (“F”). The system also includesa fuel system. The fuel system includes a deoxygenation unit fordeoxygenating a fuel in the fuel system and a fuel-oil heat exchangerlocated downstream of the deoxygenation unit, the fuel-oil heatexchanger being in thermal communication with the oil in the firstengine system and the fuel in the fuel system for transferring heat fromthe oil in the first engine system to the fuel in the fuel system.

In another exemplary embodiment of the present disclosure, a system formanaging thermal transfer is provided. The system includes a gas turbineengine having a combustor, a first engine system operable with the gasturbine engine and utilizing an oil for heat transfer, and a fuel systemfor providing fuel to the combustor of the gas turbine engine. The fuelsystem includes a fuel tank, a fuel pump located downstream of the fueltank for generating a flow of fuel, and a deoxygenation unit locateddownstream of the fuel pump for deoxygenating a fuel in the fuel system.The fuel system additionally includes a fuel-oil heat exchanger locateddownstream of the deoxygenation unit, the fuel-oil heat exchanger inthermal communication with the oil in the first engine system and thefuel in the fuel system for transferring heat from the oil in the firstengine system to the fuel in the fuel system.

In yet another exemplary embodiment of the present disclosure, a systemfor managing thermal transfer is provided. The system includes a gasturbine engine and a main lubrication oil system operable with the gasturbine engine for providing the gas turbine engine with a lubricationoil. The lubrication oil has a temperature limit of at least about 500degrees F. The system additionally includes a fuel system. The fuelsystem includes a deoxygenation unit for deoxygenating a fuel in thefuel system and a fuel-oil heat exchanger located downstream of thedeoxygenation unit in thermal communication with the lubrication oil inthe main lubrication oil system. The fuel-oil heat exchanger, duringoperation of the gas turbine engine, defines a fuel inlet temperature, afuel outlet temperature, an oil inlet temperature, and an oil outlettemperature. The fuel inlet temperature is up to about 200 degrees F.,the fuel outlet temperature is between about 450 degrees F. and about600 degrees F., the oil inlet temperature is between about 450 degreesF. and about 600 degrees F., and the oil outlet temperature is up toabout 250 degrees F.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 is a top view of an aircraft in accordance with an exemplaryembodiment of the present disclosure.

FIG. 2 is a port side view of the exemplary aircraft of FIG. 1.

FIG. 3 is a schematic cross-sectional view of an exemplary gas turbineengine according to an exemplary embodiment of the present disclosure.

FIG. 4 is a schematic view of an exemplary system for managing thermaltransfer in accordance with an exemplary embodiment of the presentdisclosure.

FIG. 5 is a schematic view of another exemplary system for managingthermal transfer in accordance with an exemplary embodiment of thepresent disclosure.

FIG. 6 is a schematic view of yet another exemplary system for managingthermal transfer in accordance with an exemplary embodiment of thepresent disclosure.

FIG. 7 is a schematic view of still another exemplary system formanaging thermal transfer in accordance with an exemplary embodiment ofthe present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to present embodiments of theinvention, one or more examples of which are illustrated in theaccompanying drawings. The detailed description uses numerical andletter designations to refer to features in the drawings. Like orsimilar designations in the drawings and description have been used torefer to like or similar parts of the invention. As used herein, theterms “first”, “second”, and “third” may be used interchangeably todistinguish one component from another and are not intended to signifylocation or importance of the individual components. The terms“upstream” and “downstream” refer to the relative direction with respectto fluid flow in a fluid pathway. For example, “upstream” refers to thedirection from which the fluid flows, and “downstream” refers to thedirection to which the fluid flows.

Referring now to the drawings, wherein identical numerals indicate thesame elements throughout the figures, FIG. 1 provides a top view of anexemplary aircraft 10 as may incorporate various embodiments of thepresent disclosure. FIG. 2 provides a port side 24 view of the aircraft10 as illustrated in FIG. 1. As shown in FIGS. 1 and 2 collectively, theaircraft 10 defines a longitudinal centerline 12 that extendstherethrough, a vertical direction V, a lateral direction L, a forwardend 14, and an aft end 16.

Moreover, the aircraft 10 includes a fuselage 20, extendinglongitudinally from the forward end 14 of the aircraft 10 towards theaft end 16 of the aircraft 10, and a pair of wings 22. The first of suchwings 22 extends laterally outwardly with respect to the longitudinalcenterline 12 from the port side 24 of the fuselage 20 and the second ofsuch wings 22 extends laterally outwardly with respect to thelongitudinal centerline 12 from a starboard side 26 of the fuselage 20.As is depicted in phantom, each of the wings 22 for the exemplaryembodiment depicted includes a fuel tank 18 housed therein. Theexemplary aircraft 10 may further include one or more additional fueltanks located elsewhere within, e.g., the fuselage 20 of the aircraft10. Further, each of the wings 22 for the exemplary embodiment depictedincludes one or more leading edge flaps 28 and one or more trailing edgeflaps 30. The aircraft 10 further includes a vertical stabilizer 32having a rudder flap 34 for yaw control, and a pair of horizontalstabilizers 36, each having an elevator flap 38 for pitch control. Thefuselage 20 additionally includes an outer surface 40.

The exemplary aircraft 10 of FIGS. 1 and 2 also includes a propulsionsystem. The exemplary propulsion system includes a plurality of aircraftengines, at least one of which mounted to each of the pair of wings 22.Specifically, the plurality of aircraft engines includes a firstaircraft engine 42 mounted to a first wing of the pair of wings 22 and asecond aircraft engine 44 mounted to a second wing of the pair of wings22. In at least certain exemplary embodiments, the aircraft engines 42,44 may be configured as turbofan jet engines suspended beneath the wings22 in an under-wing configuration. For example, in at least certainexemplary embodiments, the first and/or second aircraft engines 42, 44may be configured in substantially the same manner as the exemplaryturbofan jet engine 100 described below with reference to FIG. 3.Alternatively, however, in other exemplary embodiments any othersuitable aircraft engine may be provided. For example, in otherexemplary embodiments the first and/or second aircraft engines 42, 44may alternatively be configured as turbojet engines, turboshaft engines,turboprop engines, etc.

Referring now to FIG. 3, a schematic, cross-sectional view of anexemplary aircraft engine is provided. Specifically, for the embodimentdepicted, the aircraft engine is configured as a high bypass turbofanjet engine, referred to herein as “turbofan engine 100.” As discussedabove, one or both of the first and/or second aircraft engines 42, 44 ofthe exemplary aircraft 10 described in FIGS. 1 and 2 may be configuredin substantially the same manner as the exemplary turbofan engine 100 ofFIG. 3.

As shown in FIG. 3, the turbofan engine 100 defines an axial direction A(extending parallel to a longitudinal centerline 102 provided forreference) and a radial direction R. In general, the turbofan 10includes a fan section 104 and a core turbine engine 106 disposeddownstream from the fan section 104.

The exemplary core turbine engine 106 depicted generally includes asubstantially tubular outer casing 108 that defines an annular inlet110. The outer casing 108 encases, in serial flow relationship, acompressor section including a booster or low pressure (LP) compressor112 and a high pressure (HP) compressor 114; a combustion section 116; aturbine section including a high pressure (HP) turbine 118 and a lowpressure (LP) turbine 120; and a jet exhaust nozzle section 122. A highpressure (HP) shaft or spool 124 drivingly connects the HP turbine 118to the HP compressor 114. A low pressure (LP) shaft or spool 126drivingly connects the LP turbine 120 to the LP compressor 112.

For the embodiment depicted, the fan section 104 includes a variablepitch fan 128 having a plurality of fan blades 130 coupled to a disk 132in a spaced apart manner. As depicted, the fan blades 130 extendoutwardly from disk 132 generally along the radial direction R. Each fanblade 130 is rotatable relative to the disk 132 about a pitch axis P byvirtue of the fan blades 130 being operatively coupled to a suitableactuation member 134 configured to collectively vary the pitch of thefan blades 130 in unison. The fan blades 130, disk 132, and actuationmember 134 are together rotatable about the longitudinal axis 12 by LPshaft 126 across a power gear box 136. The power gear box 136 includes aplurality of gears for adjusting the rotational speed of the fan 128relative to the LP shaft 126 to a more efficient rotational fan speed.

Referring still to the exemplary embodiment of FIG. 3, the disk 132 iscovered by rotatable front hub 138 aerodynamically contoured to promotean airflow through the plurality of fan blades 130. Additionally, theexemplary fan section 104 includes an annular fan casing or outernacelle 140 that circumferentially surrounds the fan 128 and/or at leasta portion of the core turbine engine 106. It should be appreciated thatthe nacelle 140 may be configured to be supported relative to the coreturbine engine 106 by a plurality of circumferentially-spaced outletguide vanes 142. Moreover, a downstream section 144 of the nacelle 140may extend over an outer portion of the core turbine engine 106 so as todefine a bypass airflow passage 146 therebetween.

The turbofan engine 100 may additionally be operable with one or moreauxiliary systems to allow for proper operation of the turbofan engine100 and/or an aircraft (e.g., aircraft 10) to which the turbofan engine100 is incorporated. More specifically, for the embodiment depicted, theexemplary turbofan engine 100 is operable with a fuel system 148, a mainlubrication oil system 150, and a variable frequency generator 152. Theexemplary fuel system 148 depicted is in flow communication with a fueltank 154 (which may be configured in substantially the same manner asthe exemplary fuel tank 18 of FIGS. 1 and 2), and is configured toprovide fuel from the fuel tank 154 to a combustor of the exemplarycombustor section 116 of the turbofan engine 100. Additionally, theexemplary main lubrication oil system 150 is configured to providelubrication oil to various rotating parts or components of the turbofanengine 100. For example, the main lubrication oil system 150 mayrecirculate a lubrication oil through the engine to provide an amount oflubrication oil to various gears (e.g., within the power gearbox 136),bearings (e.g., various bearings supporting rotation of the fan 128, theLP shaft 126, and/or the HP shaft 124), and/or other rotatingcomponents. The main lubrication oil system 150 further removes anamount of heat from each of these components. Moreover, the variablefrequency generator 152 may be configured as an electric generatordriven by, e.g., an accessory gearbox (not shown) of the turbofan engine100, for generating electrical power at various rotational speeds.

It should be appreciated, however, that the exemplary turbofan engine100 depicted in FIG. 3 is by way of example only, and that in otherexemplary embodiments, the turbofan engine 100 may have any othersuitable configuration, including, e.g., any suitable number of shaftsor spools, compressors, and/or turbines. Additionally, in otherexemplary embodiments, the turbofan engine 100 may instead be configuredas any other suitable gas turbine engine, such as a turboshaft engine,turboprop engine, turbojet engine, etc.

Referring now to FIG. 4, a schematic view is provided of a system 200for managing thermal transfer in at least one of an aircraft or a gasturbine engine. For example, the exemplary system 200 depicted maymanage thermal transfer in the exemplary aircraft 10 depicted in FIGS. 1and 2, and/or the exemplary gas turbine engine 100 depicted in FIG. 3.

The exemplary system 200 of FIG. 4 generally includes a first enginesystem 202, a second engine system 204, and a fuel system 206. The fuelsystem 206 is configured for providing fuel to a combustor of the gasturbine engine via an outlet line 207, similar to the exemplary fuelsystem 148 depicted in FIG. 3. Accordingly, the exemplary fuel system206 generally includes a fuel tank 208 (which may be configured as theexemplary fuel tank 18 described above with reference to FIG. 1), a fuelpump unit 210, a deoxygenation unit 212, and a fuel metering unit 214.The fuel pump unit 210 is in fluid communication with the fuel tank 208at a location downstream of the fuel tank 208 for generating a flow offuel through one or more fuel lines 216. Additionally, the deoxygenationunit 212 is in fluid communication with the fuel pump unit 210 at alocation downstream of the fuel pump unit 210 for deoxygenating fuel inthe fuel system 206. Deoxygenating fuel in the fuel system 206 mayreduce a formation of insoluble products referred to as “coke” in thefuel when the fuel is heated above certain thresholds. Coke forms whenhydrocarbon fuel containing oxygen is heated beyond a certaintemperature (e.g. above 250° F. or 121° C.). Coke deposits within thefuel may limit a lifespan of certain components within the fuel system206 and degrade engine performance by, e.g., clogging certain fuelnozzles.

The exemplary fuel system 206 additionally includes a fuel-oil heatexchanger located downstream of the deoxygenation unit 212 and inthermal communication with the fuel in the fuel system 206. Moreparticularly, the exemplary fuel system 206 depicted includes a firstfuel-oil heat exchanger 218 operable with the first engine system 202and a second fuel-oil heat exchanger 220 operable with the second enginesystem 204. Accordingly, during operation of the fuel system 206 of FIG.4, fuel may be provided from the fuel tank 208 through the fuel pumpunit 210 and to the fuel metering unit 214. Specifically, for theembodiment depicted, fuel is pumped through a main fuel pump 222 of thefuel pump unit 210 through the fuel lines 216 to and through a boosterpump 224 within the fuel metering unit 214. Fuel is then provided to thedeoxygenation unit 212 wherein the fuel is deoxygenated. Thedeoxygenated fuel, for the exemplary system 200 depicted, is thenprovided to the second fuel-oil heat exchanger 220 wherein an amount ofheat is transferred from the second engine system 204 to thedeoxygenated fuel, and subsequently the fuel is provided to the firstfuel-oil heat exchanger 218, wherein an additional amount of heat istransferred from the first engine system 202 to the deoxygenated fuel.As is depicted, a supplemental fuel pump 226 of the fuel pump unit 210subsequently increases a pressure of the heated and deoxygenated fueland provides a flow of such fuel through a fuel filter 228 before thefuel is provided back to the fuel metering unit 214. Within the fuelmetering unit 214, the fuel is either provided via a fuel metering valve230 to, e.g., a combustor of the gas turbine engine, or through fuelbypass valve 232, wherein such fuel recirculates back through the fuelsystem 206.

The exemplary system 200 of FIG. 4 additionally includes a plurality ofbypass lines for bypassing one or both of the first fuel-oil heatexchanger 218 and the second fuel-oil heat exchanger 220. Specifically,the exemplary system 200 depicted includes a first bypass line 234having a first one-way bypass valve 236 for bypassing the first fuel-oilheat exchanger 218 and a second bypass line 238 having a second one-waybypass valve 240 for bypassing the second fuel-oil heat exchanger 220.Although not depicted, the exemplary system 200 may additionally includethree-way valves at junctures between the respective bypass lines 234,238 and fuel lines 216 for diverting a flow of fuel in the fuel lines216 through such bypass lines 234, 238 when bypass of the first fuel-oilheat exchanger 218 and/or second fuel-oil heat exchanger 220 is desired.

Referring still to the embodiment of FIG. 4, the first engine system 202is configured as a main lubrication oil system of a gas turbine engine(similar to the main lubrication oil system 150 of the exemplaryturbofan engine 100 of FIG. 3). The main lubrication oil system utilizesa high temperature oil for heat transfer, as well as to providelubrication to various bearings and other rotating parts within the gasturbine engine. The high temperature oil may be any suitable oil capableof withstanding the elevated temperatures of the exemplary system 200depicted. For example, the high temperature oil may be any suitable oilhaving a temperature limit of at least about 500 degrees Fahrenheit (°F.). Alternatively, the high temperature oil may instead have atemperature limit of at least about 550° F. It should be appreciated,that as used herein, terms of approximation, such as “about” or“approximately,” refer to being within a 10% margin of error.Additionally, as used herein, the “temperature limit” of the oil refersto a temperature at which the oil begins coking, vaporizing, orotherwise deteriorating under operational pressures.

Moreover, the oil may be a liquid at relatively low temperatures, suchthat the oil is not required to be preheated. More specifically, the oilmay define a pour temperature of less than about 0° F., such as lessthan about −10° F., such as less than about −25° F., such as less thanabout −40° F. As used herein, the “pour temperature” refers to atemperature which the oil becomes semisolid and loses its flowcharacteristics.

More particularly, in certain exemplary embodiments the high temperatureoil may be an ionic liquid, or an ionic liquid blend. Ionic liquidspossess virtually no vapor pressure. Therefore, in use, they generallypresent a low risk of atmospheric contamination and have no odour.Further, ionic liquids are generally non-flammable, thermally stable andliquid over a wide range of temperatures. However, in other embodiments,the high temperature oil may be any other suitable oil.

The exemplary main lubrication oil system of FIG. 4 may generallyinclude a circulation assembly 242 for circulating the oil through thevarious components of the engine. More particularly, in at least certainexemplary embodiments, the circulation assembly 242 of the mainlubrication oil system may include an oil pump, one or more oil supplylines, a scavenge pump, and one or more oil scavenge lines.Additionally, as is discussed above, the main lubrication oil system isoperable with the first fuel-oil heat exchanger 218 for transferringheat from the oil within the main lubrication oil system to the fuel thefuel system 206. The exemplary first fuel-oil heat exchanger 218 mayaccordingly be in fluid communication with, e.g., the circulationassembly 242 of the main lubrication oil system.

As stated, for the embodiment depicted the exemplary main lubricationoil system utilizes a high temperature oil for heat transfer.Additionally, given the position of the fuel deoxygenation unit 212upstream of the first fuel-oil heat exchanger 218, the fuel within thefuel system 206 is capable of receiving a relatively high amount of heatfrom the main lubrication oil system. For example, during operation of agas turbine engine within which the main lubrication oil system isintegrated, the first fuel-oil heat exchanger 218 may define a fuelinlet temperature T_(F1) at a fuel inlet 244, a fuel outlet temperatureT_(F2) at a fuel outlet 246, an oil inlet temperature T_(O1) at an oilinlet 248, and an oil outlet temperature T_(O2) at an oil outlet 250. Incertain exemplary embodiments, the fuel inlet temperature T_(F1) may beup to about 200° F., the fuel outlet temperature T_(F2) may be betweenabout 450° F. and about 600° F., the oil inlet temperature T_(O1) may bebetween about 450° F. and about 600° F., and the oil outlet temperatureT_(O2) may be up to about 250° F. Accordingly, with such an exemplaryembodiment, the exemplary first fuel-oil heat exchanger 218 may receivea relatively large amount of heat from the main lubrication oil systemduring operation of the gas turbine engine.

Referring still to the exemplary embodiment of FIG. 4 the exemplarysecond engine system 204 is configured as an electric generator systemalso utilizing a high temperature oil for heat transfer. Moreparticularly, for the embodiment depicted the exemplary second enginesystem 204 is configured as a variable frequency generator (VFG) system(similar to the VFG 152 discussed above with reference to FIG. 3)utilizing a high temperature oil for heat transfer. The exemplary VFGsystem generally includes a VFG module 252 and an air-oil heat exchanger254. Moreover, as is depicted, the second fuel-oil heat exchanger 220 isin thermal communication with the oil from the VFG system and the fuelfrom the fuel system 206 for removing heat from the VFG system andtransferring such heat to the fuel. Notably, the high temperature oilwithin/utilized by the VFG system may be the same or substantiallysimilar to the exemplary high temperature oil utilized by the firstengine system 202 (e.g., main lubrication oil system). Accordingly, theexemplary high temperature oil utilized by the VFG system may have atemperature limit of at least about 500° F., such as at least about 550°F. Alternatively, however, in other exemplary embodiments, the VFGsystem may utilize any other suitable high temperature oil, oralternatively may utilize any other suitable oil, such as an oil havinga temperature limit of less than about 500° F.

For the embodiment depicted, the air-oil heat exchanger 254 of the VFGsystem is located upstream of the second fuel-oil heat exchanger 220 ofthe fuel system 206. The air-oil heat exchanger 254 of the VFG systemmay be in airflow communication with, e.g., a flow of air from a fan ofthe turbofan engine. It should be appreciated, however, that in otherexemplary embodiments, the air-oil heat exchanger of the VFG system mayinstead be positioned downstream of the second fuel-oil heat exchanger220 of the fuel system 206, or alternatively, may not be included atall.

As shown, and as described above, the fuel in the fuel system 206 isconfigured to receive the total amount of heat from one or more heatexchangers (i.e., the first fuel-oil heat exchanger 218 and secondfuel-oil heat exchanger 220 for the embodiment depicted) located betweenthe fuel tank 208 and the outlet line 207. For the embodiment depicted,each of the one or more heat exchangers are configured as fuel-oil heatexchangers, such that no fuel-air heat exchangers art utilized foradding or removing heat from the fuel within the fuel system 206.Accordingly, such may result in a safer overall system 200, as a leak ina fuel-air heat exchanger may result in an undesirable pressurizedfuel-air combination.

It should be appreciated, however, that the exemplary system 200depicted in FIG. 4 is provided by way of example only. In otherexemplary embodiments, the system 200 may have any other suitableconfiguration. For example, in other exemplary embodiments, the secondengine system 204 may be any other suitable generator, or other enginesystem, or further the exemplary system 200 depicted may not include thesecond engine system 204 (e.g., the VFG system) and second fuel-oil heatexchanger 220. Alternatively, the second fuel-oil heat exchanger 220 mayinstead be located downstream of the first fuel-oil heat exchanger 218and/or may instead be in thermal communication with any other suitableengine system. Further, in other exemplary embodiments, the exemplarysystem 200 depicted may include additional fuel-oil heat exchangers inthermal communication with other engine systems. Further, the exemplarysystem 200 depicted may utilize any other suitable fuel pump unit 210and/or fuel metering unit 214. Further, one or both of the fuel pumpunit 210 and the fuel metering unit 214 may be in communication with acontroller (not shown) of the gas turbine engine and/or of an aircraftin which the gas turbine engine is installed for controlling operationof the fuel pump unit 210 and/or the fuel metering unit 214.

Furthermore, referring now to FIG. 5, providing another embodiment ofthe exemplary system 200 of FIG. 4, the first engine system202/exemplary main lubrication oil system may have any other suitableconfiguration. The exemplary system 200 of FIG. 5 is configured insubstantially the same manner as exemplary system 200 of FIG. 4. Theexemplary system 200 of FIG. 5, accordingly generally includes a fuelsystem 206; a first engine system 202 operable with a first fuel-oilheat exchanger 218 of the fuel system 206, the first engine system 202for the embodiment depicted being configured as a main lubrication oilsystem; and a second engine system 204 operable with a second fuel-oilheat exchanger 220 of the fuel system 206, the second engine system 204for the embodiment depicted being configured as a VFG system.

Notably, however, for the embodiment depicted, the exemplary mainlubrication oil system additionally includes an air-oil heat exchanger256. The air-oil heat exchanger 256 is in thermal communication with theoil flowing through the main lubrication oil system for removing anamount of heat from the main lubrication oil system. The air-oil heatexchanger 256 may receive a flow of air from, e.g., a fan of anexemplary gas turbine engine to provide such heat transfer. For theembodiment depicted, the exemplary air-oil heat exchanger 256 is locateddownstream of the fuel-oil heat exchanger of the fuel system 206.Accordingly, for the embodiment depicted, a majority of heat transferfrom the main lubrication oil system occurs between the main lubricationoil system and the fuel system 206 via the first fuel-oil heat exchanger218.

However, in other exemplary embodiments, the air-oil heat exchanger 256may instead be positioned upstream of the fuel-oil heat exchanger 218 ofthe fuel system 206, and moreover, in still other exemplary embodiments,the main lubrication oil system may additionally, or alternatively,include any other suitable heat exchangers.

Furthermore, in still other exemplary embodiments, the exemplary firstand second engine systems 202, 204 may, e.g., be in fluid and/or thermalcommunication with one another. For example, referring now to FIGS. 6and 7, providing other exemplary embodiments of the exemplary system200, the first engine system 202 is depicted in selective thermalcommunication with the second engine system 204.

The exemplary system 200 of FIGS. 6 and 7 may be configured insubstantially the same manner as exemplary system 200 of FIG. 4. Forexample, referring particularly to FIG. 6, the exemplary system 200generally includes a fuel system 206; a first engine system 202 operablewith a first fuel-oil heat exchanger 218 of the fuel system 206, thefirst engine system 202 for the embodiment depicted being configured asa main lubrication oil system; and a second engine system 204 operablewith a second fuel-oil heat exchanger 220 of the fuel system 206, thesecond engine system 204 for the embodiment depicted being configured asa VFG system.

However, for the embodiment of FIG. 6, the main lubrication oil systemis in selective thermal communication with the VFG system. Moreparticularly, a first transfer line 258 extends between the mainlubrication oil system (at a location downstream of the second fuel-oilheat exchanger 220) and the VFG system (at a location upstream of thefirst fuel-oil heat exchanger 218). Additionally, a second transfer line260 extends between the VFG system (at a location downstream of thefirst fuel-oil heat exchanger 218) and the main lubrication oil system(at a location downstream of the second fuel-oil heat exchanger 220 andfirst transfer line 258). Further, an oil-oil heat exchanger 262 ispositioned to selectively thermally connect the main lubrication oilsystem and the VFG system.

Such a configuration may allow for the main lubrication oil system toadditionally utilize the second fuel-oil heat exchanger 220 of the fuelsystem 206 to remove heat from the main locational oil system andprovide such heat to the fuel within the fuel system 206. For example,in certain exemplary aspects, such as during certain operatingconditions of the gas turbine engine, the VFG system may not generate alarge amount of heat required to be removed from the VFG system.Accordingly, the exemplary main lubrication oil system may thermallyconnect to the VFG system via the first and second transfer lines 258,260 and oil-oil heat exchanger 262. The relatively cool oil havingpassed through the second heat exchanger may be provided to the oil-oilheat exchanger 262 via line 260 to remove an amount of heat from the oilin the main lubrication oil system. After having received the heat fromthe main lubrication oil system, the oil may then be provided back tothe VFG system via line 258 (wherein such oil is provided back throughheat exchanger 220). Such a configuration may allow for the exemplarysystem 200 to better utilize all of the available heat transferresources available.

Referring now particularly to FIG. 7, the exemplary system 200 generallyincludes a fuel system 206; a first engine system 202 operable with afirst fuel-oil heat exchanger 218 of the fuel system 206, the firstengine system 202 for the embodiment depicted being configured as a mainlubrication oil system; and a second engine system 204, the secondengine system 204 for the embodiment depicted being configured as a VFGsystem. For the embodiment of FIG. 7, the main lubrication oil system isagain in selective thermal communication with the VFG system. Moreparticularly, a first transfer line 258 and a second transfer line 260each extend between the main lubrication oil system and the VFG system.Further, an oil-oil heat exchanger 262 is positioned to selectivelythermally connect the main lubrication oil system and the VFG system.

Such a configuration may allow for the main lubrication oil system toadditionally utilize the air-oil heat exchanger 254 of the fuel system206 to remove heat from the main lubrication oil system. For example, incertain exemplary aspects, such as during certain operating conditionsof the gas turbine engine, the VFG system may not generate a largeamount of heat required to be removed from the VFG system. Accordingly,the exemplary main lubrication oil system may thermally connect to theVFG system via the first and second transfer lines 258, 260 and oil-oilheat exchanger 262. The relatively cool oil of the VFG system may beprovided to the oil-oil heat exchanger 262 via line 258 to remove anamount of heat from the oil in the main lubrication oil system. Afterhaving received the heat from the main lubrication oil system, the oilmay then be provided back to the VFG system via line 260, wherein suchoil is provided through the heat exchanger 254. Such a configuration mayallow for the exemplary system 200 to better utilize all of theavailable heat transfer resources available.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A system for managing thermal transfer in atleast one of an aircraft or a gas turbine engine, the system comprising:a first engine system comprising a high temperature oil comprising anionic liquid or an ionic liquid blend for heat transfer; and a fuelsystem, the fuel system comprising: a deoxygenation unit fordeoxygenating a fuel in the fuel system; a fuel-oil heat exchanger inflow communication with the deoxygenation unit and in thermalcommunication with both the high temperature oil in the first enginesystem and the fuel in the fuel system for transferring heat from thehigh temperature oil in the first engine system to the fuel in the fuelsystem; a supplemental fuel pump in flow communication with the fuel-oilheat exchanger for increasing a pressure of the fuel; and a fuelmetering unit comprising a fuel bypass valve, a fuel metering valve, anda booster pump, wherein the fuel bypass valve is positioned at leastpartially upstream of the deoxygenation unit, wherein the fuel meteringunit is located downstream of the supplemental fuel pump and isconfigured to split substantially all of the fuel after being heated anddeoxygenated for delivery to one of a combustor and the fuel bypassvalve, wherein the fuel bypass valve is configured to send a firstportion of the fuel after being heated and deoxygenated to thedeoxygenation unit through a first bypass conduit and a second portionof the fuel after being heated and deoxygenated to the booster pumpthrough a second bypass conduit.
 2. The system of claim 1, wherein thefirst engine system is a main lubrication oil system of the gas turbineengine, the main lubrication oil system recirculating the hightemperature oil utilized for the heat transfer.
 3. The system of claim2, further comprising a second engine system utilizing a second oil forheat transfer, wherein the fuel-oil heat exchanger of the fuel system isa first fuel-oil heat exchanger, wherein the fuel system furthercomprises a second fuel-oil heat exchanger, wherein the second fuel-oilheat exchanger is in thermal communication with the second oil from thesecond engine system and the fuel from the fuel system for removing heatfrom the second engine system.
 4. The system of claim 2, wherein asecond engine system is a variable frequency generator system, andwherein a second oil utilized by the variable frequency generator systemhas a temperature limit between about 500 degrees Fahrenheit (F) andabout 550 degrees F.
 5. The system of claim 3, wherein the mainlubrication system is in selective thermal communication with the secondengine system.
 6. The system of claim 1, wherein the fuel systemcomprises a fuel tank and an outlet line extending to the combustor ofthe gas turbine engine, wherein the fuel in the fuel system isconfigured to receive the heat from the fuel-oil heat exchanger which islocated between the fuel tank and the outlet line.
 7. The system ofclaim 6, wherein the fuel in the fuel system is configured to receive atotal amount of heat from the fuel-oil heat exchanger and anotherfuel-oil heat exchanger located between the fuel tank and the outletline.
 8. The system of claim 1, wherein during operation of the gasturbine engine the fuel-oil heat exchanger defines a fuel inlettemperature, a fuel outlet temperature, an oil inlet temperature, and anoil outlet temperature, wherein the fuel inlet temperature is up toabout 200 degrees Fahrenheit (F), wherein the fuel outlet temperature isbetween about 450 degrees F. and about 600 degrees F., wherein the oilinlet temperature is between about 450 degrees F. and about 600 degreesF., and wherein the oil outlet temperature is up to about 250 degrees F.9. The system of claim 1, wherein the first engine system includes anair-oil heat exchanger located immediately upstream of the fuel-oil heatexchanger.
 10. The system of claim 1, wherein the fuel-oil heatexchanger is in flow communication with the deoxygenation unit at alocation downstream of the deoxygenation unit.
 11. The system of claim1, wherein the supplemental fuel pump in flow communication with thefuel-oil heat exchanger at a location downstream of the fuel-oil heatexchanger.
 12. The system of claim 1, wherein the high temperature oilhas a temperature limit of at least about 500 degrees Fahrenheit (F) andhas a pour temperature of less than zero degrees F.
 13. A system formanaging thermal transfer, the system comprising: a gas turbine engine;a main lubrication oil system operable with the gas turbine engine forproviding the gas turbine engine with a lubrication oil comprising anionic liquid or an ionic liquid blend; and a fuel system, the fuelsystem comprising: a deoxygenation unit for deoxygenating a fuel in thefuel system; and a fuel-oil heat exchanger in flow communication withthe deoxygenation unit and in thermal communication with the lubricationoil in the main lubrication oil system, the fuel-oil heat exchanger,during operation of the gas turbine engine, defining a fuel inlettemperature, a fuel outlet temperature, an oil inlet temperature, and anoil outlet temperature, the fuel inlet temperature being up to about 200degrees Fahrenheit (F), the fuel outlet temperature being between about450 degrees F. and about 600 degrees F., the oil inlet temperature beingbetween about 450 degrees F. and about 600 degrees F., and the oiloutlet temperature being up to about 250 degrees F.; a supplemental fuelpump in flow communication with the fuel-oil heat exchanger forincreasing the pressure of the fuel; and a fuel metering unit comprisinga fuel bypass valve, a fuel metering valve, and a booster pump, whereinthe fuel bypass valve is positioned at least partially upstream of thedeoxygenation unit, wherein the fuel metering unit is located downstreamof the supplemental fuel pump and is configured to split substantiallyall of the fuel after being heated and deoxygenated for delivery to oneof a combustor and the fuel bypass valve, wherein the fuel bypass valvesending a first portion of the fuel after being heated and deoxygenatedto the deoxygenation unit through a first bypass conduit and a secondportion of the fuel after being heated and deoxygenated to the boosterpump through a second bypass conduit.
 14. The system of claim 13,further comprising a second engine system utilizing a second oil forheat transfer, wherein the fuel-oil heat exchanger of the fuel system isa first fuel-oil heat exchanger, wherein the fuel system furthercomprises a second fuel-oil heat exchanger, wherein the second fuel-oilheat exchanger is in thermal communication with the second oil from thesecond engine system and the fuel from the fuel system for removing heatfrom the second engine system.
 15. The system of claim 14, wherein themain lubrication oil system is in selective thermal communication withthe second engine system.
 16. The system of claim 13, wherein thelubrication oil utilized by the main lubrication oil system defines apour temperature between zero degrees F. and about minus 40 degrees F.17. A method for operating a system for managing thermal transfer, themethod comprising: operating a gas turbine engine, a main lubricationoil system operable with the gas turbine engine for providing the gasturbine engine with a lubrication oil comprising an ionic liquid or anionic liquid blend, and a fuel system, the fuel system comprising adeoxygenation unit for deoxygenating a fuel in the fuel system, and afuel-oil heat exchanger in flow communication with the deoxygenationunit and in thermal communication with the lubrication oil in the mainlubrication oil system; and providing the fuel to a fuel inlet of thefuel-oil heat exchanger at a temperature of up to about 200 degreesFahrenheit (F); providing the fuel to a fuel outlet of the fuel-oil heatexchanger at a temperature between about 450 degrees F. and about 600degrees F.; providing the lubrication oil to an oil inlet of thefuel-oil heat exchanger between about 450 degrees F. and about 600degrees F.; and providing the lubrication oil to an oil outlet of thefuel-oil heat exchanger up to about 250 degrees F., wherein the fuelsystem further comprises: a supplemental fuel pump in flow communicationwith the fuel-oil heat exchanger for increasing the pressure of thefuel; and a fuel metering unit comprising a fuel bypass valve, a fuelmetering valve, and a booster pump, wherein the fuel bypass valve ispositioned at least partially upstream of the deoxygenation unit,wherein the fuel metering unit is located downstream of the supplementalfuel pump and splits substantially all of the fuel after being heatedand deoxygenated for delivery to one of a combustor and the fuel bypassvalve, and wherein the fuel bypass valve sends a first portion of thefuel after being heated and deoxygenated to the deoxygenation unitthrough a first bypass conduit and a second portion of the fuel afterbeing heated and deoxygenated to the booster pump through a secondbypass conduit.